The present invention relates to building automation systems. In particular, a wireless building control architecture implements automation of building systems.
Building automation systems include heating, ventilation and air conditioning (HVAC) systems, security systems, fire systems, or other systems. The systems are typically formed from distributed components wired together. HVAC systems may be formed with three separate tiers or architectural levels in a tree or hierarchal distribution. A floor level network provides general control for a particular floor or zone of a building. Controllers of the floor level network provide process controls based on sensor inputs to operate actuators. For example, a temperature sensor is read. An adjustment of a damper, heating element, cooling element or other actuator is determined based on a set point and the measured temperature. Other basic control functions for room comfort may be provided, such as by using single input, single output feedback loops employing proportional-integral-derivative methods. The building level network integrates multiple floor level networks to provide consistent control between various zones within a building. Panels or other controllers control distribution systems, such as pumps, fans or other central plants for cooling and heating. Building level controllers may communicate among themselves and also access floor level controllers for obtaining data. The management level network integrates control of the building level networks to provide a high level control process of the overall building environment and equipment. Single or dual level architectures may also be provided.
To reduce costs associated with wiring, wireless architectures for building automation systems have been proposed. Wireless standards provide single tier networks or multiple tier networks for implementing a single building automation process. For example, a multi-tier wireless network emulates current wired building automation systems. A controller wirelessly communicates with sensors and associated actuators. The lower level sensors and actuators provide mere input and output functions controlled by controllers. As another example, a hub and spoke control is proposed in U.S. patent application Ser. No. 10/353,142, the disclosure of which is incorporated herein. A controller may be integrated with an actuator, a sensor or combinations thereof. An additional layer or tier uses wireless communications for management of local functions as well as management of building wide subsystems, such as a chiller or building fan.
IEEE 802.15.4 standardizes wireless integrated building automation systems. Reduced function devices (RFD) with limited processing power communicate with full function devices. Full function devices (FFD) provide peer-to-peer wireless communication for controlling other reduced function devices. The standard contemplates hub and spoke physical communications path network configuration between an RFD and associated FFDs while using peer-to-peer communication between FFDs.
IEEE 802.15.4 describes self healing communications paths. Reduced function devices communicate only with full function devices according to a binding association between the two devices. If a controller or full function device malfunctions, the wireless topography may be used to link the reduced function device to a different controller or full function device according to predetermined associations. The new link forms a physical communications path for the reduced function device to communicate with other components of the network.